Myoglobin recombination at low temperature. Two phases revealed by Fourier transform infrared spectroscopy

• Published in: The Journal of biological chemistry 1987-05, Vol.262 (15), p.6959-6961
• Main Authors: Chance, M R, Campbell, B F, Hoover, R, Friedman, J M
• Format: Article
• Language: English
• Subjects: biochemical phenomena; Biological and medical sciences; carbon monoxide; Carbon Monoxide - metabolism; cold; Cold Temperature; Fourier Analysis; Fundamental and applied biological sciences. Psychology; I.R. spectroscopy; Kinetics; Marine; Molecular biophysics; myoglobin; Myoglobin - metabolism; myoglobins; Photolysis; Physeter catodon; Protein Conformation; Spectrophotometry, Infrared; Structure in molecular biology; Tridimensional structure
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(18)48185-9

The low-temperature recombination of CO with myoglobin was studied using Fourier transform infrared spectroscopy. The bound state of carbon monoxide myoglobin has two distinct conformers observed at 1926 and 1945 cm-1 with an intensity ratio of 1 to 8. The recombination of these bands after complete photolysis at 10 K followed by a temperature jump shows distinct kinetics for the two bands. Although both bands apparently follow the nonexponential kinetics originally described by Frauenfelder and co-workers (Austin, R., Beeson, K., Eisenstein, L., Frauenfelder, H., and Gunsalus, I. (1975) Biochemistry 14, 5355-5373), the 1926 cm-1 band does not appear appreciably below 70 K. In fact, after 20 min of recombination at 70 K the 1945 cm-1 band is fully recovered, while no detectable amount of the 1926 cm-1 band is present. This is the first association of a spectroscopic marker of protein substructure with reaction kinetics.